1. Field of the Invention
The present invention relates to an ink-jet recording apparatus for forming an image on a recording medium.
2. Description of Related Art
As an ink-jet printer ejecting ink droplets to a recording medium such as a recording sheet, there is known an ink-jet printer provided with four ink-jet heads from which ink droplets of four colors, for example, cyan, magenta, yellow, and black (CMYK) are ejected onto a recording sheet having transferred with an aid of a transfer structure. Such an ink-jet printer is capable of forming dots of an intended color on the recording medium, by (i) ejecting an appropriate amount of ink droplets from each of the four ink-jet heads, and (ii) mixing the colors on the recording medium. Theoretically, black can be formed by mixing the colors of cyan, magenta, and yellow. However, it is difficult to accurately form black, through such a color mixing method. In view of that, black ink accurately prepared in advance is used when black is needed.
To form a less bright color with the above mentioned ink-jet printer, black ink and a small amount of ink of the other colors (cyan, magenta, yellow) are mixed. However, since the color of the black ink is thicker than the other colors, simply mixing of the small amount of the ink of the other colors into the black ink hardly affects the color of black ink. For this reason, in a low-brightness region of an image to be recorded on a recording medium, it is difficult to express a slight difference of colors, due to a high percentage of the black ink in the region.